Causes of Hair Loss (Alopecia) in Cats

Cat with Facial Alopecia Psychogenic Alopecia on a cat There are many diseases and conditions which can cause a cat to lose hair. Some of these may be considered normal, others can indicate a serious disease is present. Most of the conditions which result in hair loss are included in the table below, though some of them may be rare. This extensive list helps you understand why a quick diagnosis may be difficult to make, and various diagnostic tests may need to be performed. The most common conditions causing hair loss are color-coded gray in the table (some may be more common in certain geographical areas).

Condition	Description	Symptoms	Diagnosis	Treatment
Allergic and irritant contact dermatitis	An allergic reaction following exposure to antibiotics applied to the skin; metals such as nickel; materials such as rubber, wool, and plastic; chemicals such as dyes and carpet deodorizers; or inflammation caused by irritating substances such as poison ivy. Generally requires multiple exposures.	Red skin and small bumps or blisters on the areas of skin that are sparsely haired and directly exposed to the offending substance; itching; hair loss in chronic conditions	Patch test, exclusion trials	Restrict exposure to the allergen or contact irritant in the cat's environment; steroids, antihistamines
Alopecia areata	Thought to be an autoimmune disorder	Patches of hair loss especially on head, neck, and body; no itching	Microscopic examination of hairs; biopsy	Usually recover spontaneously
Apocrine sweat gland cyst	Rare in cats	Single, round, smooth nodules with no hair; may appear bluish; usually filled with a watery liquid; most common on head, neck, and limbs	Physical exam; biopsy	Surgical removal is optional
Atopy (allergic inhalant dermatitis)	Allergic reaction to something the cat inhales such as pollen, house dust mites, and mold	Licking of feet, inflamed ears, itching, redness, and hair loss; sometimes development of infection or hot spots	Intradermal or serologic (blood) testing for allergies	Reduce exposure to allergen (what the cat is allergic to), steroids, omega 3 fatty acid supplements, antihistamines, shampoos, immunotherapy
Bacterial infection (pyoderma) *See Folliculitis*	Often occurs as a result of another condition such as a parasitic, allergic, or hormonal condition
Chemotherapy	Loss of hair due to chemotherapy is a concern for cat owners	Cats lose guard hairs so coat becomes soft and fuzzy; may lose whiskers	History	None, hair will regrow after chemotherapy discontinued; may regrow in a different color or texture
Cheyletiella (rabbit fur mite) mange	Infection with the Cheyletiella mite	Itching, scaliness; some hair loss, if severe	Skin scraping and microscopic examination - the mite is often very difficult to find	Pyrethrin
Congenital hypotrichosis	Congenital lack of hair	Kittens born with little or no hair; any hair they are born with is lost by 4 months of age	Physical exam; biopsy	None
Cushing's disease (hyperadrenocorticism)	Caused by an increase in corticosteroids in the body - either due to increased production by the body or as a side effect of high doses or prolonged therapy with corticosteroids	Hair loss, thinning of skin, hyperpigmentation, easy bruising, seborrhea, comedones (black heads); lethargy, increased thirst and urination, pot-bellied appearance	Adrenal gland function tests, urinalysis, chemistry panel, CBC	If due to glandular tumors, selegiline, o,p-DDD (Mitotane), or surgical removal of tumor; if due to high steroid doses, withdraw use of steroids slowly
Demodectic mange	Infection may be localized or generalized; the generalized form occurs in cats who have a deficient immune system	Hair loss, scaliness, redness, sometimes itching	Skin scraping and microscopic examination	NO Steroids! Rotenone, dilute Amitraz (Mitaban) dips, lime sulfur dips, ivermectin (off-label use*)
Drug or injection reaction	Rare skin reaction to a drug which is inhaled, given orally, or applied topically; more common with penicillins, sulfonamides, and cephalosporins; usually occurs within 2 weeks of giving the drug	Can vary widely and may include itching, hair loss, redness, swelling, papules, crusts, ulcers, and draining wounds	History of being treated with a drug, symptoms, biopsy	Discontinue offending drug; treat symptomatically
Erythema multiforme	Hypersensitivity reaction to infections or drugs; may also be caused by cancer or other diseases	Hair loss, 'bull's eye' lesions and vesicles often around mouth, ears, groin, and axilla; in some instances, ulcers develop; depression, fever	History, clinical signs, rule out other diseases causing similar signs; skin biopsy	Treat or remove underlying cause
Facial (preauricular) alopecia; normal hair loss above the eye	Normal decreased density of hair between the eye and ear	This decreased density of hair starts when cats are 14 to 20 months old; more prominent in short-haired, dark colored cats	No diagnostics necessary unless signs of skin disease are present such as redness or scaling	None - normal
Feline acquired symmetrical alopecia	Rare; originally called 'feline endocrine alopecia'; cause unknown	Symmetrical hair loss on back of thighs, abdomen, and genital areas; hair easily pulls out; no itching	Skin biopsy; tests to rule out other causes of hair loss	None
Flea allergy dermatitis (flea bite hypersensitivity)	Severe reaction by the cat to the saliva of the flea	Intense itching, redness, hair loss papules, crusts and scales; sometimes development of infection or hot spots	Presence of fleas; reaction to intradermal testing	Flea Control in the environment and on the cat; steroids and antihistamines for the itching
Folliculitis	Infection of the hair follicles; symptoms usually appear on face, neck, and head	Pustules develop in the hair follicles and open and form crusts; may itch and develop hair loss	Skin scraping; culture; biopsy; look for underlying condition such as allergy or FIV	Antibiotics, usually for 3-4 weeks; treat any underlying condition
Food allergies	Allergic reaction to something in the diet	Licking of feet, inflamed ears, itching, redness, and hair loss; sometimes development of infection or hot spots	Food elimination trials	Change in diet
Granulomas	May be due to infections; the body's reaction to foreign material such as plant material (e.g., foxtail) and suture material; other constant irritation; or unknown causes	Solid, firm nodules of varying sizes; those due to foreign bodies often have draining tracts; may develop hair loss, ulcers, and secondary infections	History, clinical signs, biopsy, surgical exploratory	Surgical removal of the foreign body (in the case of plant material, tracts may be extensive and require major surgery); antibiotics if infected; treat any other underlying cause
Hair loss during pregnancy and nursing ('blowing her coat,' telogen effluvium)	Excess shedding that can also occur in other stressful circumstances such as illness or surgery	Sudden and widespread hair loss	History, clinical signs	Treat any underlying condition; hair will grow back
Hyperthyroidism	Approximately 1/3 of cats with this disease will have skin lesions; caused by excess secretion of thyroid hormone	Hair loss; hair easily pulled out; seborrhea; cats may overgroom and cause 'hot spots'	Physical exam; blood testing for thyroid hormones	Remove part of thyroid; radioactive iodine therapy; methimazole
Injection site alopecia	Hair loss at the site of an injection of a medication or vaccine; skin may become thickened; in cats, ulcers may develop	Hair loss occurs several months after injection; area may become hyperpigmented	History and physical examination	None; the condition is permanent
Lice	Infection with several species of lice	Variable: itching, hair loss, crusts, rough hair coat	Finding lice or nits on skin or hair	Pyrethrin, ivermectin (off-label use*)
Malassezia	Usually follows some other underlying disease	Itching, redness, hair loss, greasy scales; if chronic develop hyperpigmentation	Skin scraping/smear and microscopic examination, culture	Treat underlying disease; oral ketoconazole; miconazole shampoos
Psychogenic (neurogenic) dermatitis	Self-licking in cats results in self-trauma; possible causes include anxiety, boredom, stress (e.g., new member in household)	Symmetrical hair loss, sometimes ulcers, on abdomen, groin, along the back	Exclude other causes; history important	Relieve underlying cause e.g., anxiety; restrict licking; behavior modifying medication may be necessary
Pyoderma-superficial *(see Folliculitis)*
Ringworm	Infection with several types of fungus	Hair loss, scaliness, crusty areas; some itching	Culture	Miconazole, lime sulfur dips; oral griseofulvin or itraconazole
Sebaceous adenitis	Sebaceous glands are destroyed, cause unknown; very rare in cats	Circular areas of crusts and scales on head, ears, and neck; hair pulls out easily, leaving skin exposed	Clinical signs, skin biopsy	Antiseborrheic shampoos, fatty acid supplements; in more severe cases, steroids, retinoids
Seborrhea	Can be primary (inherited) or secondary (resulting from other disease processes such as FeLV, FIP, FIV, ringworm, and parasites)	Scales; depending upon the type, may have a dry or oily coat; odor; some scratching; may see hair loss	Blood tests, skin scrapings, etc. to find underlying cause	Treat underlying cause if present; antiseborrheic shampoos; fatty acid supplements
Solar dermatosis (sunburn)	Skin reaction to sunlight; more common in cats with white ears	Redness, hair loss, and scaling on nose and ears, later crusts and ulcers	History, breed, physical exam, skin biopsy	Must avoid further sun exposure, especially 9 am - 3 pm; sunblock, steroids
Stud tail (tail gland hyperplasia)	A sebaceous gland (on the top of the tail near its base) enlarges; most often occurs in confined, unneutered males	Oily area, hair loss, and crusts on area over gland; may become hyperpigmented	Clinical signs	Castration usually does not resolve the condition; antiseborrheic shampoos, retinoids; if confined, allow cat more freedom

* off-label use: medication used to treat a condition for which it was not developed (or licensed). A large number of medications fall under this category. Research has almost always been performed to determine the effectiveness and safety of the product, but the manufacturer has not undertaken the lengthy process required for licensure.